Will WiFi be the nightmare for the UMTS/3-G network providers? When WiFi may take over some of the potential services of these providers? WLAN use TCP/IP for VoIP (Voice over IP using voice telephone via data networks) in competition with GSM, etc. A whole group of new companies and established chipmakers hardware providers and telecom companies are trying to get a piece of the action. The newest laptop and desk top computers have WiFi receivers installed already. WiFi mobile phones are under development, but a major problem is the high energy consumption of the WiFi chips.